It's long been known that France agreed in September 1956 to help Israel with its nuclear program, and the two countries cooperated closely until 1967, when de Gaulle severed the alliance following israel's occupation of Gaza & the West Bank.
France wasn't the only culprit. Britain secretly supplied 20 tons of deuterium oxide for the project, passing it off as a Norwegian-Israeli transaction (
documents). No "peaceful use" condition was imposed on the material.
The US wasn't informed of the deal, but American inspection of the Dimona facility was quietly abandoned during the 1960s in the face of Israeli stonewalling. After France ditched Israel, Washington stepped in swiftly to take its place, but by then Israel had its bomb.